1. Field of the Invention
The present invention relates to a device designed to provide a tire air valve with multiple ports in order to simultaneously admit and release air for a variety of purposes.
2. Description of the Prior Art
One of the most crucial tasks in the regular maintenance of a vehicle is checking the air pressure of tires and adding air to attain the proper pressure. Most tires have a recommended air pressure that the user should maintain to optimize performance and safety. In addition, tires that are not maintained at the proper pressure will wear faster, thus making them less economical. Most vehicle owners perform this maintenance themselves since it is a relatively simple task and most service stations provide only self-service air facilities. In the usual process, air is injected into the tire and then the pressure is checked intermittently, using a separate tire pressure-measuring device. This process is repeated until the proper pressure is attained. The procedure can be cumbersome and slows the process considerably. This system is required however with the current standard design for tire air valves since there is only one port. If, however there were two ports to access the air in the tire, air could be inserted or released through one port while the other port could be used for gauging the pressure of the air in the tire.
In the prior art there are systems for airing tires and gauging the air pressure through a single port. These designs require several mechanisms that may deteriorate with use and often are relatively inaccurate. Thus a valve design that includes two ports would greatly expand the possibilities for air supply systems, making dual task systems simpler and improving accuracy. The result would be a far more convenient design for air valves.
U.S. Pat. No. 3,230,968 to William D. Struby discloses a design for a valve stem that incorporates a pressure measuring device. This design uses a single port for air while the present invention discloses a design for a valve stem with two air ports. This lends itself to the common problems associated with using a single air port for both air gauge and air supply. Another distinction from the Struby '968 patent in the present invention is the sealing mechanism for the air ports. The present invention uses a screw cap mechanism that applies force to create a seal and can be manipulated by a key design. The Struby '968 design uses a spring that presses a seal against an orifice to cut off air flow. This seal is broken when a member is pressed to contract the spring and break the seal. Any inadvertent pressure applied to the spring can break this seal whereas the present device must be intentionally adjusted to allow the seal to be broken.
U.S. Pat. No. 3,450,147 to Donald A. Webb, is a design for a tire valve that incorporates an addition to the standard valve stem design. This design incorporates a single port design that is substantially different from the two-port design of the present invention. A plug that is mounted on a spring seals the port in the Webb '147 design. Like most designs in the prior art this seal is broken by applying pressure to a member that contracts the spring and forces the plug away from the mouth of the port. The present invention instead has a screw cap that must be adjusted to a point where the spring-mounted plug will be pressed away by the air within the tire. This eliminates the risk of inadvertent release of air due to accidental pressure on the spring. It also prevents the presence of a slow leak due to declining effectiveness of the spring.
U.S. Pat. No. 4,310,014 to James E. Parker is a patent for a mechanism that can be incorporated into the typical valve stem design to indicate when a tire has fallen below the appropriate pressure. An indicator is calibrated to an internal spring that will vary in contraction according to the pressure within the tire. This design employs a single port for inserting air and monitoring tire pressure. The present invention employs a dual port design that allows for a more accurate means for monitoring the air pressure within the tire. Also the Parker patent '014 uses the standard spring loaded seal while the present invention incorporates an adjustable cap to apply fixed pressure to ensure a tight seal.
U.S. Pat. No. 4,445,527 to Richard C. Leimbach describes a device that may be incorporated on the exterior end of the standard valve stem. This device incorporates a spring mounted seal that may be broken if the tire pressure exceeds a level high enough to contract the spring. As with all the designs in the prior art a single port is used in this design. Also there is no mechanism in the Leimbach '527 patent like the screw cap of the present invention for adjusting external pressure to ensure the seal of the valve.
U.S. Pat. No. 4,883,107 to Kenneth B. Keys discloses a variation of a device that may be incorporated on the exterior end of the standard valve stem. The purpose of this mechanism is to allow the user to insert air until the pressure exceeds the appropriate level, at which time the mechanism will release the air from the tire until the correct pressure is attained. This variation does not eliminate the two distinct features of the present invention from the prior art. Firstly only one port for the valve stem is used. Secondly no feature is included to adjust the pressure applied to the spring in order to ensure the seal.
U.S. Pat. No. Des. 419,085 to Robert Prus is a design patent for an air pressure indicator that may be incorporated to a valve stem. It has no impact on the prior art regarding the number of ports provided. It also does not incorporate a mechanism for securing the seal formed by the spring-mounted plug of the standard valve stem design.
Therefore a need exists for a novel and enhanced method for accessing and adjusting the air supply within devices designed to retain air. This need includes adaptability to many devices for measuring said air supply. In this respect, the dual outlet air valve according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of access to the air supply of air retaining devices.